1. Field of the Invention
The present invention relates generally to an image forming apparatus. More particularly, the invention relates to an image forming apparatus having an intermediate transfer roller.
1. Description of the Related Art
An image forming apparatus develops a latent image formed on a photo conductor through an electrophotographic process by a toner to form a toner image. In the image forming apparatus having an intermediate transfer roller, the toner image is once carried on the intermediate roller and then transferred and fixed to a printing medium.
In such image forming apparatus, even after transferring the toner image to the printing medium from the intermediate transfer roller, toner may reside on the surface of the intermediate roller for various reason, such as the deposition of flying toner on an unnecessary portion or deposition of excessive toner due to deterioration of a developer or from other sources.
The residual toner is composed in the image that should be formed, in the successive printing process causes degradation of a printed image.
Conventionally, in order to remove such residual toner, there has been proposed a technology, in which a cleaning blade contacts with the intermediate transfer roller under pressure and removes the residual toner on the surface of the intermediate transfer roller (Japanese Unexamined Patent Publication No. Heisei 9-114269).
However, when the cleaning blade contacts with the intermediate transfer roller and scraps the toner residing off the surface of the intermediate transfer roller, the cleaning blade directly contacts the intermediate transfer roller under pressure. When this occurs, it is possible to form a scratch on the surface of the intermediate transfer roller during a long period of use.
On the other hand, due to the possibility of a formation of a scratch, the cleaning blade cannot be urged onto the intermediate transfer roller with sufficient force. This causes difficulty in performing a satisfactory cleaning.
Also, in order to reduce the contact area, there is a technology to employ a brush form roller. However, such brush form roller may cause stripe form scratches on the intermediate transfer roller to make a stripe-like pattern to appear on the printed image to cause degradation of quality of the image.